1. Field of the Invention
The present invention relates to an apparatus and a method for processing a substrate, such as a semiconductor wafer or a glass substrate for an LCD (liquid crystal display), in a sealed processing vessel with a processing fluid including a processing gas, such as ozone gas, and a solvent vapor, such as steam.
2. Description of the Related Art
Generally known semiconductor device fabricating process includes a series of steps of coating a surface of a semiconductor wafer or an LCD substrate (hereinafter referred to as “substrate”) with a photoresist film, transferring a circuit pattern to the photoresist film by photolithography, developing the circuit pattern, and removing the photoresist film.
Recently, it is desired, in view of environmental protection, to remove the resist film without using any chemical solutions that cause problems in waste liquid disposal. A newly developed resist removing method proposed in recent years uses a processing gas, such as ozone gas (O3 gas), and a solvent vapor, i.e., a vapor of a solvent in which processing gases are resolvable, such as steam, for removing a resist film from a substrate. This method places a substrate in a processing vessel, heats and pressurizes the interior of the processing vessel, and supplies a mixed processing containing ozone gas and steam into the processing vessel.
In carrying out this previously proposed method, it is important to set the interior of the processing vessel at a predetermined temperature and at a predetermined pressure in a short time in view of carrying out the method at a large throughput. A large quantity of the processing gas and a large quantity of solvent vapor must be supplied into the processing vessel and a heater having a large heating capacity is necessary when the processing vessel has a large volume.
The substrate processing apparatus may be provided with a plurality of processing vessels to increase throughput. If the substrate processing apparatus is provided with a plurality of processing gas sources and a plurality of solvent vapor sources respectively corresponding to the processing vessels, the scale of the substrate processing apparatus will be enlarged and the cost of the substrate processing apparatus increases. Such problems in the scale and cost of the substrate processing apparatus may be solved by using a common processing fluid source for the plurality of processing vessels. However, if the processing fluid is supplied from the common processing fluid source to the plurality of processing vessels simultaneously or sequentially at time intervals, it is possible that the pressures in the processing vessels vary and the substrates are not processed properly.